package msn.client;

//#J2SE_EXCLUDE_FILE
//#PJAVA_EXCLUDE_FILE
import java.util.Enumeration;
import java.util.NoSuchElementException;

public class StringTokenizer implements Enumeration
{
  // WARNING: StringTokenizer is a CORE class in the bootstrap cycle. See the
  // comments in vm/reference/java/lang/Runtime for implications of this fact.

  /**
   * The position in the str, where we currently are.
   */
  private int pos;

  /**
   * The string that should be split into tokens.
   */
  private final String str;

  /**
   * The length of the string.
   */
  private final int len;

  /**
   * The string containing the delimiter characters.
   */
  private String delim;

  /**
   * Tells, if we should return the delimiters.
   */
  private final boolean retDelims;

  /**
   * Creates a new StringTokenizer for the string <code>str</code>,
   * that should split on the default delimiter set (space, tab,
   * newline, return and formfeed), and which doesn't return the
   * delimiters.
   *
   * @param str The string to split
   * @throws NullPointerException if str is null
   */
  public StringTokenizer(String str)
  {
    this(str, " \t\n\r\f", false);
  }

  /**
   * Create a new StringTokenizer, that splits the given string on
   * the given delimiter characters.  It doesn't return the delimiter
   * characters.
   *
   * @param str the string to split
   * @param delim a string containing all delimiter characters
   * @throws NullPointerException if either argument is null
   */
  public StringTokenizer(String str, String delim)
  {
    this(str, delim, false);
  }

  /**
   * Create a new StringTokenizer, that splits the given string on
   * the given delimiter characters.  If you set
   * <code>returnDelims</code> to <code>true</code>, the delimiter
   * characters are returned as tokens of their own.  The delimiter
   * tokens always consist of a single character.
   *
   * @param str the string to split
   * @param delim a string containing all delimiter characters
   * @param returnDelims tells, if you want to get the delimiters
   * @throws NullPointerException if str or delim is null
   */
  public StringTokenizer(String str, String delim, boolean returnDelims)
  {
    len = str.length();
    this.str = str;
    // The toString() hack causes the NullPointerException.
    this.delim = delim.toString();
    this.retDelims = returnDelims;
    this.pos = 0;
  }

  /**
   * Tells if there are more tokens.
   *
   * @return true if the next call of nextToken() will succeed
   */
  public boolean hasMoreTokens()
  {
    if (! retDelims)
      {
        while (pos < len && delim.indexOf(str.charAt(pos)) >= 0)
          pos++;
      }
    return pos < len;
  }

  /**
   * Returns the nextToken, changing the delimiter set to the given
   * <code>delim</code>.  The change of the delimiter set is
   * permanent, ie. the next call of nextToken(), uses the same
   * delimiter set.
   *
   * @param delim a string containing the new delimiter characters
   * @return the next token with respect to the new delimiter characters
   * @throws NoSuchElementException if there are no more tokens
   * @throws NullPointerException if delim is null
   */
  public String nextToken(String delim) throws NoSuchElementException
  {
    this.delim = delim;
    return nextToken();
  }

  /**
   * Returns the nextToken of the string.
   *
   * @return the next token with respect to the current delimiter characters
   * @throws NoSuchElementException if there are no more tokens
   */
  public String nextToken() throws NoSuchElementException
  {
    if (pos < len && delim.indexOf(str.charAt(pos)) >= 0)
      {
        if (retDelims)
          return str.substring(pos, ++pos);
        while (++pos < len && delim.indexOf(str.charAt(pos)) >= 0);
      }
    if (pos < len)
      {
        int start = pos;
        while (++pos < len && delim.indexOf(str.charAt(pos)) < 0);

        return str.substring(start, pos);
      }
    throw new NoSuchElementException();
  }

  /**
   * This does the same as hasMoreTokens. This is the
   * <code>Enumeration</code interface method.
   *
   * @return true, if the next call of nextElement() will succeed
   * @see #hasMoreTokens()
   */
  public boolean hasMoreElements()
  {
    return hasMoreTokens();
  }

  /**
   * This does the same as nextTokens. This is the
   * <code>Enumeration</code interface method.
   *
   * @return the next token with respect to the current delimiter characters
   * @throws NoSuchElementException if there are no more tokens
   * @see #nextToken()
   */
  public Object nextElement() throws NoSuchElementException
  {
    return nextToken();
  }

  /**
   * This counts the number of remaining tokens in the string, with
   * respect to the current delimiter set.
   *
   * @return the number of times <code>nextTokens()</code> will succeed
   * @see #nextToken()
   */
  public int countTokens()
  {
    int count = 0;
    int delimiterCount = 0;
    boolean tokenFound = false; // Set when a non-delimiter is found
    int tmpPos = pos;

    // Note for efficiency, we count up the delimiters rather than check
    // retDelims every time we encounter one.  That way, we can
    // just do the conditional once at the end of the method
    while (tmpPos < len)
      {
        if (delim.indexOf(str.charAt(tmpPos++)) >= 0)
          {
            if (tokenFound)
              {
                // Got to the end of a token
                count++;
                tokenFound = false;
              }
            delimiterCount++; // Increment for this delimiter
          }
        else
          {
            tokenFound = true;
            // Get to the end of the token
            while (tmpPos < len
                   && delim.indexOf(str.charAt(tmpPos)) < 0)
              ++tmpPos;
          }
      }

    // Make sure to count the last token
    if (tokenFound)
      count++;

    // if counting delmiters add them into the token count
    return retDelims ? count + delimiterCount : count;
  }
} // class StringTokenizer
